Pvn H,i I'UitlS

LAS.EA. 221
L. rubra has been recorded by Sars among arctic shells
occurring in newer tertiary strata in the diocese of
Christiania.
Dr. Turton was the first who noticed the curious fact
that this minute mollusk is viviparous. It does not
appear to be prolific, as seldom more than twenty young
ones are to be seen at any one time in the shell of the
parent. They are fully formed while in this stage of
growth, and their shells have even a tinge of purplishred
on each side of the beaks. Mr. Clark says the
ovary contained no young in specimens which he procured
in the winter. The same may perhaps be said of
most mollusca, whether viviparous or oviparous, as well
as of other animals the season of whose loves in a state
of nature does not commence until
"
species patefactast verna diei,
Et reserata viget genitabilis aura favoni."
A discussion took place some years ago, between
Mr. Clark on the one side, and Messrs. Alder and Han-
cock on the other,
as to the use of the anterior tube in
this species and in Kellia sub orbicularis, both of which are
Mr. Clark contended that it was an organ
viviparous.
of reproduction, in consequence of his having observed
the fry ejected through it. His opponents disputed this
uterine function, and showed that the tube serves to
own observations induce
convey water to the gills. My
me to believe that it has various uses— one for obtaining
food, another for aerating the gills,
and a third for the
expulsion of the fry. The tube seems to be expanded
or contracted at the will of the animal, being formed
merely by an overlapping
of the folds of the mantle. Its
sides are never united. The present species is rather
active in its habits. According to Mr. Clark, it imme-